1. Field of the Invention
The present invention relates generally to the fields of cellular biology and the diagnosis of neoplastic disease. More specifically, the present invention relates to a novel extracellular serine protease termed Tumor Antigen Derived Gene-14 (TADG-14).
2. Description of the Related Art
Serine proteases comprise a family of protein degrading enzymes that serve a host of biological functions including activation of blood coagulation cascades, activation of growth and angiogenic factors and degradation of extracellular matrix components (1-4). In recent years, aberrant expression of serine proteases, such as plasminogen activator have been shown to correlate positively with the invasiveness and metastatic potential of tumor cells (3, 5-6). Presumably, this occurs by increasing the ability of the tumors to degrade extracellular matrix components either directly or indirectly through the proteolytic activation of other zymogenic proteases. More significantly, the serine protease known as the prostate specific antigen (PSA) has been used successfully as a tumor marker for the early diagnosis of prostate cancer due to its abnormal prevalence in the peripheral blood of these patients (7). Serine proteases play important roles in the cascade of events involved in the malignant process, and at least for prostate cancer, they provide sufficient signal to allow detection of early disease.
The prior art is deficient in the lack of effective means of screening to identify proteases overexpressed in carcinoma. The present invention fulfills this longstanding need and desire in the art.
The present invention discloses a 1343 base pairs long TADG-14 cDNA (SEQ ID No: 6) which encodes a 260 amino acid protein (SEQ ID No: 7) overexpressed in carcinoma. The availability of the TADG-14 gene opens the way for a number of studies that can lead to various applications.
In one embodiment of the present invention, there is provided a DNA encoding a TADG-14 protein selected from the group consisting of: (a) isolated DNA having the sequence of SEQ ID No. 6; (b) isolated DNA which is complementary to the isolated DNA of (a); and (c) isolated DNA differing from the isolated DNAs of (a) and (b) above in codon sequence due to the degeneracy of the genetic code.
In another embodiment of the present invention, there is provided a vector capable of expressing the DNA of the present invention, as well as host cell transfected with the vector that express a TADG-14 protein.
In yet another embodiment of the present invention, there is provided an isolated and purified TADG-14 protein coded for by DNA selected from the group consisting of: (a) isolated DNA having the sequence of SEQ ID No. 6; and (b) isolated DNA differing from the isolated DNA of (a) in codon sequence due to the degeneracy of the genetic code, and which encodes a TADG-14 protein.
In still yet another embodiment of the present invention, there is provided a method of detecting expression of TADG-14 mRNA, comprising the steps of: (a) contacting mRNA obtained from a cell with a labeled hybridization probe having the sequence of SEQ ID No. 6; and (b) detecting hybridization of the probe with the mRNA, wherein the presence of hybridization indicates expression of TADG-14 protein.
In another embodiment of the present invention, there is provided a method of vaccinating an individual against TADG-14 protein, comprising the step of (a) inoculating an individual with a TADG-14 protein or fragment thereof which lacks TADG-14 protease activity. Typically, inoculation with the TADG-14 protein or fragment thereof elicits an immune response in the individual, thereby vaccinating the individual against TADG-14. Generally, the individual has cancer, is suspected of having cancer or is at risk of getting cancer. Preferably, the TADG-14 fragment is a 9-residue fragment up to a 20-residue fragment, and more preferably, the 9-residue fragment is SEQ ID Nos. 17, 18, 41, 42, 47, 48, 53, 56, or 64.
In another embodiment of the present invention, there is provided a method of producing activated immune cells directed toward TADG-14, comprising the steps of exposing immune cells to a TADG-14 protein or fragment thereof which lacks TADG-14 protease activity. Usually, exposure to the TADG-14 protein or fragment thereof activates the immune cells, thereby producing activated immune cells directed toward TADG-14. Generally, the immune cells are B cells, T cells or dendritic cells. Preferably, the dendritic cells are isolated from an individual prior to exposure to a TADG-14 protein or fragment thereof, and then reintroduced into the individual subsequent to the exposure. Typically, the individual has cancer, is suspected of having cancer or is at risk of getting cancer. Preferably, the TADG-14 fragment is a 9-residue fragment up to a 20-residue fragment, and more preferably, the 9-residue fragment is SEQ ID Nos. 17, 18, 41, 42, 47, 48, 53, 56, or 64.
In another embodiment of the present invention, there is provided an immunogenic composition, comprising an immunogenic fragment of a TADG-14 protein and an appropriate adjuvant. Preferably, the TADG-14 fragment is a 9-residue fragment up to a 20-residue fragment, and more preferably, the 9-residue fragment is SEQ ID Nos. 17, 18, 41, 42, 47, 48, 53, 56, or 64.
In another embodiment of the present invention, there is provided an oligonucleotide having a sequence complementary to SEQ ID No. 6, as well as a composition comprising the oligonucleotide and a physiologically acceptable carrier. Additionally, there is provided a method of treating a neoplastic state in an individual in need of such treatment, comprising the step of (a) administering to the individual an effective dose of the above-described oligonucleotide.
Other and further aspects, features, and advantages of the present invention will be apparent from the following description of the presently preferred embodiments of the invention given for the purpose of disclosure.